1. Field of the Invention
The present invention relates to electrophotographic printing apparatus, and more particularly, to apparatus for transporting toner material to a development zone.
2. Prior Art
References that disclose auger mechanisms for transporting toner material include U.S. Pat. No. 4,813,531 issued Mar. 21, 1989 to Tannascoli et al., entitled DEVELOPER TRANSPORT APPARATUS, U.S. Pat. No. 4,926,790 issued May 22, 1990 to Nash, entitled AUGER UNIT, U.S. Pat. No. 4,163,614 issued Aug. 7, 1979 to Vock discloses an auger system for transporting toner material using a flexible rotating helical member to advance the toner particles.
With high speed electrographic printing machines there is often very little time available between the moment when uncharged toner from the toner hopper enters the development housing and the first time it reaches the development housing zone where it is required to be well charged. On the other hand, the distance between the toner hopper and the development housing is typically quite far for both architectural and customer convenience reasons.
Another object of the present invention provide a toner transport apparatus that uses the distance between the toner hopper and the developer housing to premix the toner with the developer, by augering some of the developer up to the toner hopper and start to mix the toner and developer at that point.
An object of the present invention is to provide a toner transport apparatus that allows more time for toner charging and ease the charging rate requirements on the toner itself.